French Navy Nuclear Inventory Updated: M51.3 Ballistic Missile Becomes Operational

The French Ministry of the Armed Forces has announced that the new M51.3 intercontinental ballistic missile has reached operational capability on Le Triomphant-class nuclear submarines.

The announcement was made on the Ministry’s official website.

The M51.3 is the third upgrade of the M51 ballistic missile, which remains the core element of the naval component of France’s nuclear deterrent. According to the ministry, the M51.3 features improved range, accuracy, and enhanced capability to defeat missile defense systems. It carries the new TNO-2 warhead, developed under a modeling program by the Atomic Energy Commission (CEA).

Tests of the M51 family have been underway since 2006. The first launch of the M51.3 took place on November 18, 2023, from a land-based site. Previous tests in 2020, 2021, and 2023 were also successful.

In September 2025, the DGA procurement agency signed a contract with ArianeGroup to develop the next modification, the M51.4, aimed at further improving range, accuracy, and survivability against missile defense systems.

“The introduction of M51.3 and TNO-2 completes the multi-year modernization of French naval strategic forces and lays the groundwork for further upgrades with M51.4 in the coming years,” the French Ministry of the Armed Forces stated.

The French M51 ICBM is a three-stage, solid-fuel, submarine-launched ballistic missile deployed on Le Triomphant-class submarines. It replaced the M45 model in 2010 and is the foundation of France’s ocean-based nuclear deterrent (FOST).

The missile is launched from vertical tubes (16 on each submarine) and uses an inertial/astronomical guidance system designed to resist interference and missile defenses. It is equipped with countermeasures to defeat interception.

Evolution of the system includes the M51.1 version with TN-75 warheads, the improved M51.2 with the first TNO warhead, and now the M51.3, which completed full qualification tests and was officially accepted into service on October 24, 2025, by decision of the French Minister of the Armed Forces.

ArianeGroup is the prime contractor, working under the supervision of the DGA.

Flight tests of the M51 have been ongoing since 2006 at the DGA Biscarrosse test range and from submarines. A launch on June 12, 2020, from the submarine Le Téméraire confirmed the missile’s ability to reach intercontinental range.

In November 2023, the first qualification launch of the M51.3 was conducted, paving the way for entry into service in October 2025.

Exact specifications remain classified. Open sources indicate the missile is approximately 12 meters long, 2.3 meters in diameter, weighs around 50 tons at launch, and has a range between 8,000 and 10,000 km. It carries multiple independently targetable reentry vehicles (MIRV) and countermeasures against missile defenses.

The French Navy maintains 48 ICBMs for three operational submarines, while a fourth is typically in deep maintenance. This aligns with the national doctrine of maintaining “minimum sufficient deterrence.” Transitioning to the M51.3 and later the M51.4 is expected to keep the naval component effective through the 2030s.

Militarnyi previously reported that France has officially begun production of the M51.4 missile, which will become the main armament for the next-generation SNLE-3G submarines.